Address allocation to psus, service arrangement and passenger cabin

ABSTRACT

In the case of a passenger cabin of an aircraft with the service arrangement, the PSUs are installed on a support structure in the passenger cabin.

BACKGROUND OF THE INVENTION

The invention relates to a method for allocating a respective address toa plurality of PSUs (Passenger Service Units) of a service arrangementfor a passenger cabin of an aircraft. The invention also relates to theservice arrangement and the passenger cabin.

DISCUSSION OF THE PRIOR ART

It is known from practice for PSUs to be incorporated into a cabinmanagement system via a multiplicity of individual connection wires.This requires a very large amount of cabling and modifications can onlybe made at a very high cost, since the aircraft cabling has to beadapted with every modification.

SUMMARY OF THE INVENTION

The present invention is directed to the improvement of theincorporation of PSUs.

The method of the present invention serves to allocate a respectiveaddress to a plurality of PSUs. The PSUs form part of a servicearrangement for a passenger cabin of an aircraft. The aircraft is, inparticular, a passenger aircraft.

The service arrangement creates the following underlying conditions forthe method: The service arrangement contains a coding means. Thisextends in an installation space along an extension line. Theinstallation space serves to accommodate or install the PSUs. In theinstalled state of the PSUs in the passenger cabin, the installationspace forms a subspace of the internal space of the passenger cabin. Theextension line is, in particular, a straight line which extends in theinstalled state in the passenger cabin in the longitudinal direction ofthe aircraft. The coding means has coding values, differing on apair-by-pair basis, of a coding parameter at different positions on theextension line at which PSUs are installable. In other words, thepresence of identical coding values at the installation positions of twoPSUs is avoided in any given configuration of PSUs. A continuouspositioning of PSUs, in particular, is thus possible. The geometricextension of a PSU automatically creates a distance between themeasuring points on the coding means (installation positions). Two PSUscannot be installed at the same location.

The service arrangement contains the aforementioned plurality of PSUs.The PSUs are installed along the extension line in the installationspace at one of the respective installation positions on the extensionline. This concerns, in particular, the installed state when the servicearrangement is installed in the passenger cabin.

In particular, each of the PSUs has a sensor. The sensor serves todetect the respective coding value of the coding means at theinstallation position of the respective PSU. The service arrangementfurthermore contains a head unit for communication with the PSUs whichis, in particular, connected to the PSUs via a communication channel.

In the method, a start command is transmitted to all PSUs. Inparticular, the head unit transmits the start command to all PSUs. Inparticular, the start command is transmitted via the communicationchannel.

In response to the start command, the respective coding value isdetermined for each of the PSUs at the installation position of therespective PSU. In particular, each of the PSUs determines itsrespective coding value. In particular, the coding value is determinedby means of the sensor.

A waiting time is then determined for the respective PSU from therespective determined coding value for each of the PSUs according to atime rule. In particular, each of the PSUs determines its waiting time.The time rule is the same for all PSUs. The time rule maps, inparticular, the coding values linearly onto waiting times. The time ruleand coding values are matched to one another in such a way that allwaiting times differ from one another on a pair-by-pair basis for allpossible configurations (choice of installation positions) of PSUs. Notwo PSUs therefore have the same waiting times.

Beginning at the time when the start command is received, the expiry ofthe respective waiting time is then awaited for each PSU. At the time ofexpiry of the waiting time, a response is transmitted from therespective PSU to the main unit, in particular via the communicationchannel. In particular, the PSU waits for the respective amount of time,and therefore has an internal time management and/or also transmits therespective response itself. Durations of the start command are ignoredhere, i.e. the transmission time of the start command is equal to thereception time at all PSUs. Due to the guarantee of different waitingtimes, all responses of all PSUs are therefore transmitted at differenttimes. The waiting time therefore begins with the transmission of thestart command. The response is transmitted when the waiting time ends.The duration of the responses is again ignored.

In response to the reception of a respective response at the head unit,one of the addresses differing respectively on a pair-by pair basis isallocated to the PSU which had transmitted the corresponding receivedresponse. The allocation is performed, in particular, by the head unititself. The responses are allocated to the respective PSU whichtransmitted the response, in particular by means of a uniqueidentification which is contained in the response. A respectively uniqueor different address is thus allocated to each of the successivelyresponding PSUs. All PSUs can now be addressed or communicated withsingly and individually using their respective individual differentaddress.

The time intervals between two responses are sufficiently separated bythe time rule or the parameters of the coding values and therefore thedimensioning of possible waiting times in order to be able to uniquelydistinguish the responses and therefore the respectively respondingPSUs. A unique address allocation can thus be performed.

An automatic addressing method for a PSU in an aircraft is producedaccording to the invention. To summarize briefly, a unique address isallocated to each PSU using the coding means.

In one preferred embodiment, the communication channel is used as a databus and the address is used as the bus address of the respective PSU inthe data bus. The data bus is thus suitable for any given datacommunication between the head unit and the PSUs, in particular for thetargeted individual transmission of audio, video and other data betweenany given bus participants (head unit, PSUs).

In one preferred embodiment, the waiting time is determined on the basisof the time rule as the coding value, multiplied by a constant. Thistherefore produces a particularly simple linear mapping of the codingvalues onto waiting times. Different waiting times are thus guaranteedfor different coding values. The guarantee of different coding values atall conceivable installation positions for every conceivableconfiguration of PSUs thus ensures the difference in waiting times.

In one preferred embodiment, the above-mentioned communication channelforms at least part of a power supply arrangement of the PSUs. Thecommunication on the communication channel is implemented in the form ofa power line communication on the power supply arrangement. No separatesignal paths or communication paths are thus necessary for the powersupply and the communication connection of the PSUs, thereby reducingcosts and effort.

In one preferred embodiment, the addresses are allocated to the PSUs inascending order in the sequence of the incoming responses. Since, asexplained above, it is ensured that no two responses of two PSUs arrivesimultaneously, it is also ensured that all PSUs obtain differentascending addresses.

The present invention is further directed to a service arrangement for apassenger cabin of an aircraft. The service arrangement and at leastsome of its embodiments and the respective advantages have already beenexplained accordingly in connection with the method according to theinvention.

The service arrangement contains a coding means extending in aninstallation space (part of the service arrangement) for the PSUs alongan extension line, wherein the coding means has coding values, differingon a pay-by-pair basis, of a coding parameter, at different installationpositions on the extension line. The service arrangement contains theplurality of PSUs which are installable or are installed in theinstalled state along the extension line in the installation space atone of the respective installation positions on the extension line.

In particular, each of the PSUs has a sensor detecting the respectivecoding value of the coding means at its installation position.

The service arrangement contains a head unit which is connected to thePSUs for communication, in particular via a communication channel (partof the service arrangement).

The service arrangement contains a control unit which is configured tocarry out the method according to the invention. In particular, the headunit and/or the PSUs are configured to carry out the method according toone of the preceding claims, i.e. they form at least a part of or theentire control unit.

In one preferred embodiment, the coding parameter is an electricalpotential or electrical voltage. A coding parameter of this type can, inparticular, be generated in an aircraft simply and at low cost by acoding means. A coding parameter of this type can furthermore be furtherprocessed by simple and low-cost sensors.

In one preferred variant of this embodiment, in the case of voltages,the electrical voltage is non-zero at any of the installation positions.In the case of potentials, the potential does not correspond to areference potential used in the measurement, in particular that of thesensor, at any of the installation positions. Zero measurements cantherefore be recognized unequivocally as errors, since, in theerror-free case, a non-zero voltage or potential difference must alwaysbe determined as a coding value.

In one preferred variant of this embodiment, the coding means is aresistor element, in particular a resistor wire, at the longitudinalends of which along the extension line a non-zero voltage is presentduring operation. A current thus flows through the resistor elementduring operation. The voltage may, in particular, be a DC or AC voltagewhich, in particular, has an amplitude or amount which is constant atleast for the duration of the address allocation. The electricalpotential thus inevitably drops continuously along the resistor element,so that a different potential or voltage is inevitably present as avalue of the coding parameter at each potential installation location.

In one preferred embodiment, the service arrangement contains a railsystem installable in the passenger cabin with at least one rail for themechanical connection in each case of at least one of the PSUs in eachcase with one or more rails. The rail extends, in particular, over atleast two, in particular over all, possible installation locations forPSUs. In particular, a simple reconfiguration of the PSUs throughdisplacement along the rail is thus possible. The invention offers thefacility to carry out an automatic address allocation to all PSUsfollowing any displacement.

In one preferred variant of this embodiment, the rail system can beintegrated into an overhead bin of the passenger cabin. A particularlysimple installation and also any given reconfiguration of the PSUs inthe installation space, in particular below the bins, is thus possible.In particular, in the installed state, the rails of the rail system runalong the longitudinal direction of the bins in the aircraft. In theevent of a reconfiguration, seats or rows of seats in an aircraft arenormally shifted or moved in the longitudinal direction of the aircraft,which necessitates an adjustment of the respective PSUs in preciselythis longitudinal direction. This can be done in a particularly simplemanner by means of rails running in this direction.

In one preferred variant of this embodiment, at least one of the railsis configured for the power supply of the PSUs and/or at least one ofthe rails is configured for the communication of the PSUs with oneanother and/or with the control unit, in particular for the formation ofthe communication channel. Along with the mechanical retention of thePSUs, the rails thus fulfil further functions, i.e. the power supplyand/or communication connection of said PSUs. In particular, two railsare provided for the power supply. In particular, the same rails areprovided simultaneously for the communication connection in the sense ofa power line communication. The communication channel thus forms part ofthe rail system. This results in a particularly simple and low-costdesign.

In one preferred variant of this embodiment, at least one of the railscontains or forms the coding means. In particular, a third rail isprovided along with the aforementioned two rails for this purpose.

In one preferred embodiment, the head unit and/or the control unitand/or at least one of the PSUs contain(s) an interface to a cabinmanagement system of the passenger cabin and/or to a power orcurrent/voltage supply of the passenger cabin and/or to an oxygen masksignal of the passenger cabin and/or a voltage converter and/or, in thecase of at least one rail, these elements have an electrical powerconnection and/or signal connection to the rail.

By means of the interface to the cabin management system, thecommunication channel or data bus can have a data communicationconnection to said cabin management system and all PSUs can thereforealso communicate with the cabin management system. Electric power orenergy, in particular, can be provided for the rail system and thus forthe supply of the PSUs by means of the connection to the power supply.By means of the connection to the oxygen mask signal, the correspondingfunctionality can also be made available via the communication channeland/or the rail system.

In the case of a rail system comprising at least one rail, the head unithas, in particular, a power and/or signal connection to the rail. Thesupply power, in particular, can thus be fed into the rail system or thedata connection of the rail system can thus be implemented.

The present invention is further directed to passenger cabin of anaircraft. The passenger cabin and at least some of its embodiments andthe respective advantages have already been explained accordingly inconnection with the method according to the invention and the servicearrangement according to the invention.

The passenger cabin contains a service arrangement according to theinvention. The PSUs are installed on a support structure in thepassenger cabin. The support structure is, in particular, a structuralpart of the cabin, in particular an overhead bin. The installation isperformed, in particular, by means of the aforementioned rail system.

The invention is based on the following realizations, observations orconsiderations and also comprises the following embodiments. Theembodiments are also referred to partly for simplification as “theinvention”. Here, the embodiments may also contain parts or combinationsof the aforementioned embodiments or may correspond thereto and/or maypossibly also include hitherto unmentioned embodiments.

According to the invention, further facilities are provided forsimplifying an incorporation of PSUs into the cabin management systemand the aircraft layout, and also for simultaneously reducing themanufacturing costs of the aircraft manufacturer. Power linecommunication can be used here. According to the invention, a PSU isconnected in an aircraft via a three-conductor rail system. Thenecessary bus address of the PSU is calculated by means of a conductorwhich is designed as a resistor wire.

A rail system for connecting the PSUs is proposed according to theinvention. The communication takes place via the power supply. Twoconductor rails are required here. A third conductor rail is designed asa resistance conductor. Here, 28 V DC are connected at the start of therail system. A terminating resistor is provided at the end of the railsystem. This ensures that a minimum voltage of, for example, 5 V DC isset at the end (must be non-zero if interruptions are also to bedetectable). The supply voltage and the communication are connected tothe bus in a head unit. Said head unit starts the bus configuration viaa command (start command). Each PSU (or a control unit) connected to therail system now determines a unique bus address from the voltage (codingvalue) measured at the local position (installation position). Since thevoltage decreases continuously on the resistance conductor, there is noambiguity. The response time is also derived from the measured voltagevalue, so that no bus collision occurs.

According to the invention, the bus address in a rail system isdetermined by means of a dedicated voltage drop in the resistanceconductor.

An intelligent flexible PSU (iFlexPSU) is created according to theinvention. This results in an intelligent, movable, modular, scalable,flexible and future-oriented PSU family for a multi-program platformuse. Thanks to the power supply via the communication bus, it requiresonly three connections instead of a multiplicity of individual wirings.The PSU is installed and connected by means of a rail system which canbe integrated into overhead bins. In combination with an automaticaddressing capability, the installation, configuration andreconfiguration can be carried out in a few minutes.

The PSU family enables a very cost-effective (with standard functions)or high-performance solution (with extended functions: wireless seatmonitoring, extended cabin temperature control, video, predictive healthmonitoring, passenger information, safety instructions, etc.). Standardfunctions are, in particular, “fasten seat belts” sign, reading light,call button for cabin crew, call display, no smoking sign, “PEDs inflight mode” sign). Video functions are, in particular, a moving map,safety videos, advertising, passenger guidance or local video storage.

The PSU family offers the following benefits for original equipmentmanufacturers and airlines: simple and quick to install, substantialreduction in aircraft manufacturing costs, simple and fast change ofLOPA (Location of Passenger Accommodation), operational efficiencyimprovement (especially with high-end PSUs with extended functionality),weight reduction, retrofit capability, extended functionality forpassengers and airline and future-oriented product, cost saving due toreduced cabling, reduction in aircraft manufacturing time, simple andfast installation in the final production line, reduction in weight,volume and complexity.

The PSU enables, in particular, a smart passenger cabin reconfiguration,of the type known, for example, from the publication entitled “‘CrystalCabin Award/These are 2017's best concepts for the aircraft cabin’,Crystal Cabin Award Association, do Hamburg Aviation, Wexstrasse 7,D-20355 Hamburg,http://www.crystal-cabin-award.com/cca-news-realeases/article/these-are-2017s-best-concepts-for-the-aircraft-cabin.html”.

The invention is based on a flexible combination of power linecommunication, a method for supporting automatic PSU addressing and arail system concept for flexible installation and positioning, includingreliable electrical connections.

The PSU is, in particular, connected via the rail system to the headunit. It contains the necessary electronics for a low-cost or high-endsolution. Both versions are exchangeable. Future applications can besimply integrated. The mechanical system can be designed in such a wayas to support a simple installation and removal.

The rail system contains two lines for power and communication and oneline with a higher resistance for automatic addressing purposes.Rail-to-rail connectors allow a simple pre-integration, for example inoverhead bins. The connection elements can be designed with great carein terms of environmental requirements.

The head unit is connected to the CMS (Cabin Management System), theaircraft power supply and the “oxygen mask trigger signal” from thecockpit. The head unit converts the aircraft power to 28 V for the PSUbus (power supply) and also incorporates the communication information(communication channel) on said PSU bus.

The oxygen masks can also be triggered with a different electronicsolution with the appropriate design safety level, implemented in thehead unit and the PSU.

The PSU enables the original equipment manufacturers to further reducetheir production costs and reduce the aircraft manufacturing time. Theoriginal equipment manufacturers and the airlines are given a highdegree of flexibility in terms of modification of the LOPAs andimprovement of functionality with regard to operation, maintenance andpassenger comfort.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, effects and advantages of the invention are set out inthe following description of one preferred example embodiment of theinvention, and also in the attached figures. In a schematic diagram:

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a passenger cabin of an aircraft with a servicearrangement,

FIG. 2 shows a flow diagram for an address allocation method.

FIG. 1 shows a section of an aircraft 2 (not shown in detail), here apassenger aircraft or its passenger cabin 4. Only some overhead bins 6from said passenger cabin are indicated symbolically. A rail system 8 isfitted on the underside of the overhead bins 6 facing towards rows ofseats (not shown), said rail system having a total of three rails 10 a-cand being shown symbolically or functionally (indicated by a dottedarrow) for clarification in FIG. 1. The rail system 8 forms part of aservice arrangement 12 which is installed in the passenger cabin 4.

The service arrangement 12 furthermore contains a coding means 14 whichextends along an extension line 16. In the present case, the codingmeans is designed as a rail 10 c, and for this reason the extension line16 is also shown again symbolically in FIG. 1. The extension line 16extends within an installation space 18 which represents a roofed partof the passenger cabin 4.

The installation space 18 is furthermore provided for the purpose ofinstalling PSUs in it as required, here according to the arrangement ofthe rows of seats (not shown), in each case at a correspondinglyrequired installation position 22 a-e on the extension line 16. In theexample, the service arrangement 12 contains five PSUs 20 a-e.

The overhead bins 6 thus form a support structure 25 for the PSUs 20 a-eor the service arrangement 12.

The coding means 14 has a coding parameter P, here an electricalpotential. Coding values Pa-e of the coding parameter P differ on apair-by-pair basis at all installation positions 22 a-e. In FIG. 1, theelectrical potential is related to a reference potential M, here groundpotential. In relation to the potential P, the respective potentialdifference P-M is therefore referred to synonymously as the voltage U.

Each PSU 20 a-e has a sensor 24 which detects the respective codingvalue Pa-e of the coding parameter P at the respective installationposition 22 a-e. As indicated symbolically, the detection is performedhere through high-impedance tapping of the respective potential (codingparameter) P on the rail 10 c at the installation positions 22 a-e.

The service arrangement 12 furthermore contains a head unit 26 which isconnected to the PSUs 20 a-e via a communication channel 28. In theexample, the rails 10 a,b are used for the power supply of the PSUs 20a-e. The communication channel 28 is formed by a power linecommunication on the rails 10 a,b. The communication channel 28therefore forms part of a power supply arrangement 27 (rails 10 a,b forthe power supply) of the PSUs 20 a-e. The communication on thecommunication channel 28 is implemented in the form of a power linecommunication on the power supply arrangement 27. The rails 10 a,b aretherefore configured for the power supply of the PSUs 20 a-e and for theformation of the communication channel 28.

The coding parameter P is generated in the present case in such a waythat a potential, here of P=28 V (in relation to the reference potentialM=0V), is applied or fed in by the head unit 26 at a first end 30 a ofthe rail 10 c. The coding means 14 is a resistance element, here aresistance wire. A terminating resistor 32 which, together with theresistance wire, is dimensioned so that a 5V drop occurs over theterminating resistor 32 is connected at the opposite end 30 b. Apotential P=5 V is therefore present at the end 30 b. On the entirecoding means 14, no potential P therefore corresponds to the referencepotential in the form of the reference potential M=0V. The rail 10 c orthe coding means 14 is therefore also referred to as the address cable.

The characteristic of the coding parameter P in the form of the voltageU in V over a length l of the extension line 18 in m is shownsymbolically in a diagram in FIG. 1. The ends 30 a,b of the rail 10 cand the installation positions 22 a-e of the PSUs 20 a-e are thereforeshown in the drawing.

The head unit 26 furthermore has an interface 34 to a cabin managementsystem (not shown) of the passenger cabin 4, and also an interface 36 ora power input to a voltage supply (similarly not shown) of the passengercabin 4, and also an interface 38 to an oxygen mask signal (similarlynot shown) of the passenger cabin 4.

The head unit 26 has an electrical power connection to the rails 10 a,bin order to ensure the power supply of the PSUs 20 a-e. It also has asignal connection to the rails 10 a,b in order to exchange correspondingdata with the communication channel 28 formed accordingly on the rails10 a,b. The head unit 26 and the PSUs 20 a-e together form a controlunit 29 which is configured to carry out the method explained below withFIG. 2.

FIG. 2 shows symbolically in a diagram 38 the characteristic of thecoding parameter P here in the form of a voltage U in V in relation tothe reference potential M, plotted over a length l of the passengercabin 4 in m. The characteristic is shown over the entire length of thecoding means 14 from the end 30 a to the end 30 b. In particular, therespective coding values Pa-e at the respective installation positions22 a-e are shown in the drawing.

FIG. 2 shows a flow diagram for a method for allocating a respectiveaddress Aa-e to the PSUs 20 a-e.

In a step S1, a new addressing is started.

In a step S2, the head unit 26 transmits a start command 40 via thecommunication channel 28 to all PSUs 20 a-e.

In a step S3, each of the PSUs 20 a-e, in response to receiving thestart command 40, determines the respective coding value Pa-e of thecoding parameter P at its respective installation position 22 a-e bymeans of its respective sensor 24.

In a step S4, each of the PSUs 20 a-e determines a respective waitingtime Wa-e from the determined coding values Pa-e by means of the sametime rule 42 (shown by way of example in FIG. 1 for the PSU 20 a only).The determination is carried out in the form of a multiplicationWa-e=K*Pa-e of the coding value Pa-e by a constant K.

In a step S5, the respective PSU 20 a-e waits for its respective timeWa-e as from the time when the start command 40 is received. At the timewhen the waiting time Wa-e expires, the respective PSU 20 a-e transmitsa respective response Ra-e to the head unit 26.

In a step S6, the head unit 26 allocates an address Aa-e to therespective PSU 20 a-e which transmitted the respective response Ra-e.Steps S5 and S6 are carried out, in particular, in nested form(indicated by a dotted arrow) for all PSUs 20 a-e.

In a query step F1, the number of PSUs 20 a-e to which an address Aa-ehas been allocated is checked against the known number of PSUs 20actually installed in the passenger cabin 4. If the number matches (Y,Yes), the addressing is ended in a step S7. If the number does not match(N, No), an error counter Z initially set to 0 is incremented by thevalue one in a step S8.

The error counter Z is checked in a query step F2. If the error counterZ exceeds a permitted limit, here the value 5 (Y), the method is endedwith the “addressing error” status in a step S9. If the limit is notexceeded (N), the method returns to step S2.

If the addressing method is successfully completed with step S7, thecommunication channel 28 is used as a data bus and the addresses Aa-eare used as bus addresses of the respective PSU 20 a-e in the data bus.

REFERENCE NUMBER LIST

-   2 Aircraft-   4 Passenger cabin-   6 Overhead bin-   8 Rail system-   10 a-c Rail-   12 Service arrangement-   14 Coding means-   16 Extension line-   18 Installation space-   20 a-e PSU-   22 a-e Installation position-   24 Sensor-   25 Support structure-   26 Head unit-   27 Power supply arrangement-   28 Communication channel-   29 Control unit-   30 a,b End-   32 Terminating resistor-   34 Interface-   36 Interface-   38 Interface-   40 Start command-   42 Time rule-   P Coding parameter-   Pa-e Coding value-   M Reference potential-   U Voltage-   Aa-e Address-   Wa-e Waiting time-   K Constant-   l Length-   Ra-e Response-   Z Error counter-   S1-8 Step-   F Query step

What is claimed is:
 1. A method for allocating a respective address(Aa-e) to a plurality of PSUs of a service arrangement for a passengercabin of an aircraft, wherein the service arrangement contains: a codingmeans extending along an extension line in an installation space for thePSUs, wherein the coding means has coding values (Pa-e), differing on apair-by-pair basis, of a coding parameter (P) at different installationpositions on the extension line at which PSUs are installable, theplurality of PSUs which are installed along the extension line in theinstallation space at one of the respective installation positions onthe extension line, a head unit for the communication with the PSUs, inwhich: a start command is transmitted to all PSUs, in response to thestart command, the respective coding value (Pa-e) is determined at theinstallation position of the respective PSU, a respective waiting time(Wa-e) is determined from the respective coding value (Pa-e) of arespective PSU according to a time rule, a response (Ra-e) istransmitted to the head unit for each of the PSUs on expiry of itswaiting time (Wa-e) as from the start command, in response to thereception of a respective response (Ra-e) at the head unit, one of theaddresses (Aa-e) differing on a pair-by-pair basis is allocated to thePSU which transmitted the received response (Ra-e).
 2. The methodaccording to claim 1, wherein a communication channel between the headunit and the PSUs is used as a data bus and the address (Aa-e) is usedas the bus address of the respective PSU in the data bus.
 3. The methodaccording to claim 1, wherein the waiting time (Wa-e) is determined onthe basis of the time rule as a coding value (Pa-e), multiplied by aconstant (K).
 4. The method according to claim 1, wherein acommunication channel between the head unit and PSUs forms at least partof a power supply arrangement of the PSUs and the communication on thecommunication channel is implemented in the form of a power linecommunication on the power supply arrangement.
 5. The method accordingto claim 1, wherein, the addresses (Aa-e) are allocated in ascendingorder in the sequence of the responses (Ra-e) arriving at the head unit.6. A service arrangement for a passenger cabin of an aircraft, with acoding means extending along an extension line in an installation spacefor a plurality of PSUs, wherein the coding means has coding values(Pa-e), differing on a pair-by-pair basis, of a coding parameter (P) atdifferent installation positions on the extension line at which PSUs areinstallable, with the plurality of von PSUs which are installable alongthe extension line in the installation space at one of the respectiveinstallation positions on the extension line, with a head unit which isconnected to the PSUs via a communication channel, with a control unitwhich is configured to carry out the method according to claim
 1. 7. Theservice arrangement according to claim 6, wherein the coding parameter(P) is an electrical potential or an electrical voltage.
 8. The servicearrangement according to claim 7, wherein the electrical voltage isnon-zero or the potential does not correspond to a reference potential(M) for the potential at any of the installation positions.
 9. Theservice arrangement according to claim 7, wherein the coding means is aresistor element at the longitudinal ends of which along the extensionline a non-zero voltage is present during operation.
 10. The servicearrangement according to claim 6, wherein the service arrangementcontains a rail system installable in the passenger cabin with at leastone rail for the mechanical connection to the PSUs.
 11. The servicearrangement according to claim 10, wherein the rail system can beintegrated into overhead bins of the passenger cabin.
 12. The servicearrangement according to claim 10, wherein at least one of the rails isconfigured for the power supply of the PSUs and/or at least one of therails is configured for the communication of the PSUs with one anotherand with the control unit.
 13. The service arrangement according toclaim 10, wherein at least one of the rails contains or forms the codingmeans.
 14. The service arrangement according to claim 6, wherein it hasan interface to a cabin management system of the passenger cabin and/oran interface to a power supply of the passenger cabin and/or aninterface to an oxygen mask signal of the passenger cabin and/or avoltage converter and/or, in the case of at least one rail, anelectrical power connection and/or a signal connection to at least onerail.
 15. A passenger cabin of an aircraft, with a service arrangementaccording to claim 6, wherein the PSUs are installed on a supportstructure in the passenger cabin.